<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<form action="#" method="post">
			<p>
				用户名:
				<input type="text"  name="username" required/>
				<input type="submit" name="" value="提交" />
			</p>
		</form>
	</body>
</html>
